This invention relates to blood fractionation and more particularly to the separation of a blood coagulation Factor IX preparation from plasma by the selective adsorption of Factors II, IX and X.
The process of blood coagulation is a complicated physiological activity that involves the interaction of numerous substances found in normal whole blood. It is known that certain factors associated with the blood coagulation mechanism are absent or seriously deficient in certain individuals. In those patients suffering from classical hemophilia, antihemophilic factor A (AHF, Factor VIII) is deficient. In those patients afflicted with hemophilia B, plasma thromboplastin component (PTC, Factor IX) is missing from the blood.
Several other factors which are important in the coagulation mechanism are Factors II, VII and X. As with Factors VIII and IX, these other factors also are deficient or absent in certain individuals. Factors II, VII and X are usually associated with Factor IX in the fractionation of blood plasma into various fractions, and a concentrate of these four factors has come to be known as the prothrombin complex.
In the development of modern blood banking programs involving the collection and storage of large quantities of blood and blood components, the establishment of adequate preservation systems is critical. Since World War II it has been common practice to collect blood in a solution of citric acid, sodium citrate and dextrose known as ACD blood. The problem of preserving blood is much simplified, however, when it is reduced to preservation of various blood components since it is easier to meet the environmental requirements of the separate components than of whole blood.
Moreover, it is wasteful and even detrimental to the patient to administer more blood components than required. Thus, the hemophiliac needing certain blood coagulation factors ideally should be given only those factors required or at least a purified concentrate of these factors containing a reduced level of unneeded factors.
The fractionation of blood to obtain blood coagulation Factors VIII and IX and the prothrombin complex is well known. Most fractionation methods require the separation of Factor VIII from the plasma or other starting material prior to the separation of Factor IX or the prothrombin complex. For example, Factor VIII is frequently first separated from plasma as a cryoprecipitate or by precipitation with glycine or polyethylene glycol as described in U.S. Pat. Nos. 3,631,018 and 3,652,530 and references cited therein.
Various prior methods of blood fractionation for the preparation of the prothrombin complex include the barium sulfate adsorption method described by Fowell in U.S. Pat. No. 2,999,791 and the tricalcium phosphate adsorption method disclosed by Soulier et al, La Presse Medicale 72, 1223-28 (1964). Tullis discloses the use of DEAE-cellulose ion exchanger for the production of a prothrombin complex, New England Journal of Medicine 273, 667-74 (1965) while the corresponding use of DEAE-Sephadex is described by Wado and Mozen in U.S. Pat. No. 3,717,708. Andersson et al in U.S. Pat. No. 3,920,625 further describe the use of DEAE-Sephadex specifically for the preparation of Factor IX concentrates. Use of polyethylene glycol for the production of prothrombin complex is taught by Fekete and Shanbrom in U.S. Pat. Nos. 3,560,475 and 3,682,881. Aluminum hydroxide and other such gel materials also are known as useful in the concentration of prothrombin complex factors as seen from Bidwell, U.S. Pat. No. 2,867,567.
As distinguished from all of the foregoing methods, in the present invention a Factor IX preparation is separated from plasma such that it also contains Factors II and X but not Factor VII which is usually contained in the prothrombin complex concentrates of the prior art. Moreover, the Factor IX preparation of this invention advantageously can be separated from the plasma prior to the separation of Factor VIII.